This invention relates to a fuel injection nozzle unit for internal combustion engines such as diesel engines, and more particularly to a fuel injection nozzle unit capable of controlling the lift of the nozzle needle.
It is generally required to vary the injection rate through an injection nozzle in order to maintain proper combustion conditions of an internal combustion engine over various operating regions of same, and the most effective way of varying the injection rate is to control the lift of the nozzle needle. A fuel injection nozzle unit adopting this concept of controlling the lift of the nozzle needle is already known, e.g., from Japanese Provisional Utility Model Publication (Kokai) No. 57-172167.
However, the conventional fuel injection nozzle unit is difficult to fabricate and too large in axial size, since it is constructed such that the lift of the nozzle needle is controlled by rotating a lift adjusting screw to change the axial position of a stopper for the nozzle needle.